Field of the Invention
The present invention concerns an inflatable and deflatable seal.
Such a seal is intended to ensure sealing between two surfaces, that is, to prevent the ingress of any solid or of any fluid between those two surfaces.
The problem is particularly delicate when these surfaces must be made mobile with respect to each other. An inflatable and deflatable seal then constitutes an effective system, for all that is needed is a simple variation in the pressure of a fluid inside the seal to break or make, durably, fluid-tight sealing between two surfaces even if they have surface defects or great irregularities in planeness.
Inflatable and deflatable seals, consisting of profiled bars made of an elastic material provided with inflation connections linking them to a suitable pneumatic system have already been used in the branch of aeronautical, naval, nuclear and mechanical industries. These profiled bars generally have a U-shaped cross-section whose base may be fixed by cementing or any other mechanical means, on one of the two surfaces to be brought into contact or, the more often, in a groove in that surface.
A profiled bar of the preceding type is generally defined by the ratio H/h, H being the height of its transversal cross-section in the inflated state and h being the height of its transversal cross-section in the rest state. It is required to obtain a low value for h, that is, a slight bulk of the deflated seal and of the recess which is necessary for it; moreover, it is an advantage to have available seals having a great height H, to bring two surfaces spaced very far apart together. Now, pneumatic seals known up till now make it possible to obtain a value of the ratio H/h equal at most to 2 and the more often in the order of 1.6 to 1.85.
The aim of the present invention is to produce a pneumatic seal whose shape is such that the value of the ratio H/h may be very much greater than 2.